PURPOSE: To solve a problem such as the calking process of a conductive pin, the dangling process of the pin and the following defective connection by projecting solder filled in a through-hole to the outside of the through-hole provided in a base.

CONSTITUTION: A semiconductor element 2 mounted on a base 1 is covered with a silicon gel 8. A through-hole is provided in the base 1, the through-hole is filled with solder and the solder is projected beneath the through-hole. The projection 7 of the solder from the back surface of the base 1 is melted and a package is installed on the surface of the base 1. This solves a problem such as the calking process of a conductive pin, the dangling process of the pin and the following defective connection.